During the fueling of vehicles, in particular aircraft utilized in military applications, large amounts of fuel must be moved within the shortest possible time period from a hydrant system or a tank car into the vehicle tank which is to be filled. A problem during this fueling operation involves the last twenty to thirty meters from the tank car or the hydrant system to the tank which is to be filled. It is known to use hoses here which are provided at one end with the filler-neck coupling, so that the fueling operation can occur directly after connection to the fill opening. Here, hoses with a steel or Perlon insert are used which, as a rule, have nominal diameters of 21/2 to a maximum of 3". In particular, in the case of lengths of over 20 meters, only hoses with small diameters are used, due to the high weight, since they otherwise can hardly be handled when the hose must be pulled or carried. A transport of the hoses in an unrolled condition, for example to several connections in the cases of a hydrant system, is hardly possible because of high friction with the ground. In every case, the durability of the hose is substantially reduced through this. With respect to the durability of the material, on the one hand an aging of the material occurs here and, on the other hand, damage due to cutting of the steel insert occurs, for example when a tank car drives over the hoses. This damage, in particular if we are dealing with inner damage, can be recognized only with great difficulty, so that a hose must be exchanged periodically for safety reasons after a certain duration of use which involves considerable expense.
A further decisive disadvantage when using a hose is that it can be utilized for defueling only in a limited manner and only in a special design which increases costs. Furthermore, the hose can be emptied only by lifting it, which also brings about a considerable disadvantage. However, it has proved disadvantageous that the coupling of the hose to the aircraft coupling is difficult due to the heavy weight and the tension of the hose and that, due to the hose and its weight, a high stress on the aircraft coupling takes place and can result in damage. Furthermore, pressure relief in hoses is very difficult to realize. Pressure relief is necessary, since the high expansion coefficient of aircraft gasoline causes a great volume increase during a temperature increase. The thus caused pressure increase stretches the hoses, so that they can no longer be bent. In the reverse case, namely for falling temperatures, an underpressure is created in the hose, so that it collapses and the reinforcement of the hose breaks.
The above disadvantages resulting from the use of hoses for fueling shows that, aside from handling difficulties and high wear, which are to be expected, the fueling time can hardly be reduced by increasing the nominal diameter of the hose, because of the increased disadvantage in handling which is created by the enlargement of the nominal diameter. Hoses represent, because of these susceptibilities and the heat sensitivity, a high safety risk, in particular when used near hot turbines and motors or when used near running turbines, as is the case during rapid fueling of military aircraft. The described disadvantages require, at the same time, an intensive servicing and testing operation for the hose which must take place before and after each fueling operation.
A basic purpose of the invention is to provide a head piece for fueling systems of the above-mentioned type which can be connected directly to tank cars, fueling arms or a hydrant system, which can be designed easily and without any handling difficulties with a diameter of 4" or more, which is subject to minimal wear, which can be operated in a simple manner and can be connected almost moment-free to the aircraft coupling or some other coupling, which requires little service, which is suited for both the fueling and defueling, which can be stored in a small space, and which can be used near running turbines and motors without any safety risk.